Not everyone who is into self-improvement finds it through martial arts either. It is easy to fall into the trap of feeling self-righteous because we've managed to stick with aikido for a number of years, even through injuries and life circumstances that get in the way. It's easy to start to get too proud of ourselves when we see people drop out.

But there are those, as you point out, for whom aikido is not the right path. I agree with you that aikido, "...may be suitable to learn for everyone, but its not for everyone." But I disagree that those who choose not to study aikido are uninterested in self-improvement.

Alternatives include attending one's church, temple, mosque, or otherwise following a religeous discipline, having a regular exercise program, studying yoga, reading a lot, traveling, etc. Any of those activities can lead to self-improvement...or not.

Nor does studying aikido necessarily lead to self improvement. There have been a few times in my short time training (just under five years), where I've caught myself becoming arrogant, or too proud of my accomplishments. Hardly an improvement.